U.S. patent application number 14/888880 was filed with the patent office on 2016-06-09 for medical device for inserting into a hollow organ of the body.
This patent application is currently assigned to ACANDIS GMBH & CO. KG. The applicant listed for this patent is ACANDIS GMBH & CO. KG. Invention is credited to Giorgio CATTANEO, David KLOPP, Frank NAGL.
Application Number | 20160158039 14/888880 |
Document ID | / |
Family ID | 50639513 |
Filed Date | 2016-06-09 |
United States Patent
Application |
20160158039 |
Kind Code |
A1 |
CATTANEO; Giorgio ; et
al. |
June 9, 2016 |
MEDICAL DEVICE FOR INSERTING INTO A HOLLOW ORGAN OF THE BODY
Abstract
The invention relates to a medical device for inserting into a
hollow organ of the body. The device has a compressible and
expandable lattice structure made of webs, which are integrally
connected to each other by web connectors and which bound closed
cells of the lattice structure, wherein the web connectors each
have a connector axis extending between two cells which, in a
longitudinal direction of the lattice structure, are adjacent to
each other. During the transition of the lattice structure from the
production state to a compressed state, the web connectors rotate
in such a way that an angle between the connector axis and a
longitudinal axis of the lattice structure changes, in particular
increases, during the transition of the lattice structure from a
completely expanded production state to a partially expanded
intermediate state.
Inventors: |
CATTANEO; Giorgio;
(Karlsruhe, DE) ; KLOPP; David; (Remchingen,
DE) ; NAGL; Frank; (Karlsruhe, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ACANDIS GMBH & CO. KG |
Pfinztal |
|
DE |
|
|
Assignee: |
ACANDIS GMBH & CO. KG
Pfinztal
DE
|
Family ID: |
50639513 |
Appl. No.: |
14/888880 |
Filed: |
April 30, 2014 |
PCT Filed: |
April 30, 2014 |
PCT NO: |
PCT/EP2014/058862 |
371 Date: |
February 9, 2016 |
Current U.S.
Class: |
623/1.16 ;
606/200 |
Current CPC
Class: |
A61F 2210/0014 20130101;
A61F 2230/0004 20130101; A61F 2250/0006 20130101; A61B 17/221
20130101; A61F 2/013 20130101; A61F 2/91 20130101; A61F 2002/91575
20130101; A61F 2002/016 20130101; A61F 2/915 20130101 |
International
Class: |
A61F 2/91 20060101
A61F002/91; A61B 17/221 20060101 A61B017/221; A61F 2/01 20060101
A61F002/01 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2013 |
DE |
10 2013 104 550.2 |
Claims
1. A medical device for inserting into a hollow organ of the body,
the medical device comprising: a lattice structure comprises an
expanded state, a compressed state, and an intermediate state, the
intermediate state being between the expanded state and the
compressed state; the lattice structure having a longitudinal axis
defining a longitudinal direction; the lattice structure comprising
a plurality of webs and a plurality of closed cells, each web of
the plurality of webs bounding one cell of the plurality of closed
cells; and a plurality of web connectors, each web connector
integrally connecting a first web of the plurality of webs to a
second web of the plurality of webs, each web connector having a
connector axis extending between a first cell and a second cell of
the plurality of cells, the first cell and the second cell are
adjacent in the longitudinal direction; wherein when the lattice
structure is in the expanded state, the connector axis and the
longitudinal axis are offset from each other by a first angle; and
wherein when the lattice structure is in the intermediate state,
the connector axis and the longitudinal axis are offset from each
other by a second angle; the second angle being larger than the
first angle.
2. The medical device of claim 1, wherein the first angle is 5
degrees or less.
3. The medical device of claim 1, wherein the first angle is
substantially 0 degrees.
4. The medical device of claim 1, wherein when the lattice
structure is in the expanded state, at least one web connector of
the plurality of web connectors has a first rotational direction;
when the lattice structure is in the compressed state, the at least
one web connector has a second rotational direction, the second
rotational direction being different than the first rotational
direction.
5. The medical device of claim 1, wherein each cell of the
plurality of closed cells comprises a cell tip, the connector axis
being along a shortest distance between a first cell tip of the
first cell and a second cell tip of the second cell.
6. The medical device of claim 5, wherein each of the first cell
tip and the second cell tip comprise a curvature having a vertex,
the vertex forming an end point of the connector axis.
7. The medical device of claim 1, further comprising a rotation
point around which a respective web connector rotates, wherein when
the lattice structure is in intermediate state, the rotation point
is disposed at an intersection of the longitudinal axis and a
transection of the longitudinal axis by the connector axis.
8. The medical device of claim 7, wherein the web connector is
formed point-symmetrically relative to the rotation point. Medical
device according to claim 7, characterized in that the web
connector (20) is formed point-symmetrically in relation to the
rotation point (16).
9. The medical device of claim 1, wherein the plurality of webs
further comprises a third web and a fourth web, wherein the first,
second, third, and fourth web are disposed adjacent to the
respective web connector; wherein the first web and the third web
are arranged on a diametrically opposite side to the second web and
the fourth web.
10. The medical device of claim 9, further comprising a plurality
of neutral fibers, a first neutral fiber being associated with the
first web and the third web, a second neutral fiber being
associated with the second web and the fourth web, the first,
neutral fiber being positioned on the second neutral fiber.
11. The medical device of claim 9, further comprising a plurality
of neutral fibers, a first, set of neutral fibers being associated
with the first, web and the third web, a second set of neutral
fibers being associated with the second web and the fourth web, the
first neutral fiber being positioned on the second neutral fiber;
wherein the first set of neutral fibers is arranged so that th e
neutral fibers of the first set of neutral fibers are in a
staggered fashion to each other; and wherein the second set of
neutral fibers is arranged so that the neutral fibers of the second
set, of neutral fibers are aligned with each other.
12. The medical device of claim 11, wherein each of the first web
and the second web comprises a broadened root.
13. The medical device of claim 9, wherein the first web and the
second web are S-shaped proximal to the respective web connector or
the second web and the fourth web have a straight shape proximal to
the respective web connector.
14. The medical device of claim 1, wherein the web connector has a
wasp-waisted shape.
15. The medical device of claim 1, wherein the connector axis is
offset to the longitudinal axis by 5 degrees or less when the
lattice structure has an expansion degree of 15% or less or 90% or
more.
16. The medical device of claim 1, wherein the connector axis is
offset from the longitudinal axis by 15 degrees to 20 degrees when
the lattice structure has an expansion degree of 40% to 50%.
17. The medical device of claim 1, wherein the connector axis is
offset from the longitudinal axis by 12 degrees to 18 degrees when
the lattice structure has an expansion degree of 60% to 70%.
18. The medical device of claim 1, wherein the connector axis is
offset from the longitudinal axis by 5 degrees to 12 degrees when
the lattice structure has an expansion degree of 80% to 90%.
19. The medical device of claim 1, wherein the lattice structure is
self-expandable.
20. The medical device of claim 1, wherein the lattice structure
comprises nitinol.
21. The medical device of claim 1, where when the lattice structure
is in the expanded state, the lattice structure has a
cross-sectional diameter between 3.5 mm and 6 mm.
22. The medical device of claim 1, wherein the lattice structure
has, in the circumferential direction, between three and six
immediately adjacent cells that form a cell ring and are bounded by
four webs each, of which the first web and a third web has a first
web width. and the second web and a fourth web each has a second
web width, wherein a ratio between the first web width and the
second web width is between 1:1.1 and 1:1.5.
2. The medical device of claim 1, wherein the lattice structure
has, in the circumferential direction, more than 12 immediately
adjacent cells that form a cell ring and are bounded by four webs
each, of which the first web an d a third web each has a first web
width, and the second web and a fourth web each has a second web
width, wherein a ratio between the first web width and the second
web width is between 1:1.1 and 1:3.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a medical device for insertion into
a hollow organ of the body.
[0003] 2. Background of the Invention
[0004] Devices of this type are known, for example, as stents or
thrombectomy devices. Stents or thrombectomy devices are used to
treat a variety of diseases of the blood vascular system and
frequently have an expandable lattice structure. The lattice
structure is guided to the treatment site via a catheter. To this
effect, the lattice structure assumes a radially compressed state
so that it can be pushed along within the catheter canal.
[0005] In order to ensure good guidability, it is useful for the
lattice structure to have a relatively high axial stiffness, at
least in the guiding state. This prevents the lattice structure
from radially widening when subjected to an axial force, causing
increased friction at the interior wall of the catheter. In the
known stents or thrombectomy devices, an increased axial stiffness
leads to a reduction of cross-axial flexibility, making it more
difficult to place the lattice structure in small, tightly wound
blood vessels, such as are found in the area of the cerebral
vascular system, for example.
[0006] As a rule, when designing medical devices with an expandable
lattice structure, as is the case with stents and thrombectomy
devices, it is necessary to find a compromise between high
cross-axial flexibility and a sufficient radial force. The radial
force serves to expand the lattice structure radially and to
support it against a vascular wall. By changing the dimensions,
such as those of the web cross sections, the cross-axial
flexibility can be increased, so that the device or lattice
structure can be easily guided through small, highly wound blood
vessels. At the same time, however, the radial expandability or
radial force is diminished. Consequently, there is a risk that the
radial force will no longer be sufficient to securely anchor the
lattice structure within the blood vessel.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a
medical device for insertion into a hollow organ of the body,
having sufficient radial force for anchorage inside the organ, good
axial stiffness to guide it through a catheter, and high
cross-axial flexibility so that the device is easy to guide through
small, hollow, highly wound vessels of the body.
[0008] The invention is thus based on the idea of providing a
medical device for insertion into a hollow organ of the body,
having a compressible and expandable lattice structure of webs that
are integrally connected to each other by web connectors that
delimit closed cells of the lattice structure. Each web connector
has a connector axis that extends between two cells that, in a
longitudinal direction of the lattice structure, are adjacent to
each other. During the transition of the lattice structure from the
production state to a compressed state, the web connectors rotate
in such a way that an angle between the connector axis and a
longitudinal axis of the lattice structure changes, in particular
increases, during the transition of the lattice structure from a
completely expanded production state to a partially expanded
intermediate state.
[0009] In principle, the lattice structure of the medical device of
this invention can be of one piece. The webs of the lattice
structure can be cut from a tubular blank by a laser cutter, for
example. The cut-out areas form the cells that are delimited by the
webs. The invention preferably entails a lattice structure having a
closed cell design. The cells are thus completely enclosed by webs.
In particular, the cells can have an essentially rhomboidal basic
shape. In other words, each cell is preferably delimited by four
webs.
[0010] Each web connector that integrally forms a part of the
lattice structure can therefore connect four webs with each other.
The web connectors essentially form the crossing points of the
webs.
[0011] Compressing or expanding the lattice structure alters the
height and width of the individual cells of the lattice structure.
Rotating the web connectors affects the degree of change in the
height and width of the cell. In particular, the rotation of the
web connectors results in a varying, dynamically changing
relationship between cell height and cell width. This results in a
comparatively high flexibility of the lattice structure,
particularly in a cross-axial direction. In particular, rotating
the web connectors allows the lattice structure to take on an oval
shape when guided through narrow hollow body organs. The lattice
structure, which at least in some sections can have a cylindrical
cross section, can thus assume an oval cross-sectional geometry
when it is guided through a curved blood vessel. As a result, the
medical device can also be inserted in very small hollow body
organs or blood vessels with pronounced vascular curvatures.
[0012] The angle between the connector axis and the longitudinal
axis in the production state and/or in a compressed guiding state
of the lattice structure can be a maximum of 5 o, in particular a
maximum of 4 degrees, in particular a maximum of 3 degrees, in
particular a maximum of, in particular a maximum of 1 degrees.
Certain embodiments of the invention allow for the connector axis
in the production state and/or in a compressed guiding state of the
lattice structure to be aligned parallel to the longitudinal axis
of the lattice structure. In particular, in the production state
the connector axis can be aligned parallel, and in a partially
expanded intermediate state of the lattice structure the connector
axis can be aligned at an angle to the longitudinal axis of the
lattice structure. Aligning the connector axis in the production
state parallel to the longitudinal axis of the lattice structure
ensures that the lattice structure has high axial stability, since
the cells and webs, arranged longitudinally adjacent to each other,
support each other in this manner.
[0013] In general, the rotation of the web connectors increases the
flexibility of the lattice structure, specifically without
impairing stability in the expanded or implanted state. Flexibility
is thus increased without diminishing the radial force.
[0014] The rotation of the web connector occurs preferably on a
plane of the wall of the lattice structure. In general, the lattice
structure can be cylindrical in sections, with the cylindrical
surface area defining the wall plane. In other words, the web
connector can rotate about a rotational axis that is positioned
vertically on the longitudinal axis of the lattice structure.
[0015] In a preferred embodiment of the medical device of this
invention, the connector axis is aligned parallel to the
longitudinal axis of the lattice structure in a compressed state,
in particular in a guiding state. In particular, [the embodiment]
can provide for the connector axis to be aligned parallel to the
longitudinal axis of the lattice structure, both in the production
state and the compressed state, in particular in the guiding state.
Specifically, the web connector can change the rotational direction
during the transition of the lattice structure from the production
state to the compressed state, in particular the guiding state.
[0016] The guiding state corresponds to a compressed state, wherein
the lattice structure has a degree of expansion sufficiently small
to keep the lattice structure within a guiding system. The degree
of expansion can be 10% or less. In this way, the lattice structure
can be introduced into small guiding systems, such as catheters,
with ease. In general, in intermediate states of the lattice
structure, in particular between the guiding state and the
production state, [the invention] allows for each web connector to
have a connector axis that is aligned at an angle to the
longitudinal axis of the lattice structure.
[0017] It is generally pointed out that any reference to an angle
between the longitudinal axis of the lattice structure and the
connector axis of the web connector within the framework of the
present application actually relies on a projection of the
longitudinal axis of the lattice structure in the wall plane, i.e.,
the plane of the web connectors. The angle between the connector
axis and the longitudinal axis of the lattice structure is thus
shown particularly in a lateral view of the medical device or
lattice structure.
[0018] The connector axis preferably corresponds to the shortest
distance between the tips of two cells located longitudinally on
opposite sides of the web connector. The lattice structure
generally comprises a plurality of cells arranged both
longitudinally and circumferentially in relation to the lattice
structure. The cells are separated from each other by webs and web
connectors. In particular, the web connectors separate cells from
each other in the longitudinal direction of the lattice structure.
The shortest distance between two cells that are arranged
immediately adjacent to each other constitutes the connector axis.
The connector axis thus extends along a line through the web
connector, the said line extending from a first cell to a
longitudinally adjacent second cell. The shortest connecting line
between the two cells, by way of the web connector, corresponds to
the connector axis.
[0019] In a further preferred embodiment of the invention, each of
the adjacent cells of the lattice structure that are arranged
longitudinally comprises a cell tip with a curvature. The curvature
can have a maximum or a vertex that forms an end point of the
connector axis. In general, webs that are arranged adjacent to each
other in a circumferential direction of the lattice structure can
be merged in a web connector at their longitudinal ends. This can
create a curvature between adjacent webs arranged in a
circumferential direction that simultaneously represents a cell
boundary. In particular, the curvature delimits a cell tip,
specifically the tip of a closed cell that preferably has a
rhomboidal basic form. The corners of the rhomboid essentially form
the cell tips. These are not necessarily pointy in the sense of a
sharp delimitation, but can be curved. The curvature can generally
take the form of a parabola, thereby creating a maximum.
Preferably, the maximum or the vertex of the curvature forms the
end point of the connector axis.
[0020] In a further preferred embodiment of the device of this
invention, the connector axis transects, at least in a partially
expanded state of the lattice structure, the longitudinal axis of
the lattice structure at an intersection that forms a rotational
point around which the web connector rotates. The rotational point
can simultaneously form a symmetry point. In particular, [the
invention] can provide for the web connector to be
point-symmetrical with respect to the rotational point.
[0021] In principle, four webs can each be arranged on a web
connector, wherein a first and third web and a second and fourth
web are arranged on diametrically opposing sides. Specifically, a
first web can be arranged diametrically opposite to a third web,
and a second web diametrically opposite a fourth web. Each web can
have a neutral fiber. The neutral fiber corresponds to a line or
area of the longitudinal section of the web, the length of which
does not change when the web is deformed. Preferred embodiments
allow in each case for a neutral fiber of the second and third web
to be positioned vertically upon the neutral fibers of the first
and third web. Generally, the neutral fiber of the second web can
be aligned vertically to the neutral fiber of the first web. The
neutral fiber of the fourth web can be aligned vertically to the
neutral fiber of the third web. In principle, other angles are
possible as well. The neutral fibers can, for example, enclose an
angle between two webs connected within the web connector, said
angle measuring a maximum of 90 degrees, in particular a maximum of
75 degrees, in particular a maximum of 55 degrees, in particular a
maximum of 50 degrees, in particular a maximum of 45 degrees.
[0022] The neutral fibers of the second and the fourth web can be
arranged in alignment with each other. In other words, the first
and the third web can share a continuous neutral fiber. It is
therefore preferred for the neutral fibers of the second and the
fourth web to be arranged staggered to each other. In other words,
the neutral fibers of the second and fourth web can meet the
neutral fibers of the first and third web at a distance from each
other. This enhances the rotation of the web connector and thus the
flexibility of the lattice structure.
[0023] The second and the fourth web can each have a broadened
root. The webs usually have a width that is constant over most of
the web length. In the area of the web connector, particularly at
the transition to the web connector, diametrically opposing webs at
least, namely the second and the fourth web can have a broadened
root. This increases the stability of the web connector and
particularly that of the entire lattice structure.
[0024] The second and fourth web can take an S-shaped course in the
area of the web connector. The first and third web, particularly
the neutral fiber thereof, can essentially take a straight course.
In particular, the second and fourth web can have a bend that
transitions into an end section of the web, particularly an angular
end section, facilitating the transition into the web connector.
The bend or the kink forms a deformation zone that contributes to
the compression or, respectively, the expansion of the lattice
structure.
[0025] Overall, an expansion or compression is achieved, which in
general means a radial change of the size of the cross section of
the lattice structure by means of the deformation of the webs of
the lattice structure. The bend or the kink at the web ends at the
transition into the web connector, creating defined sites where the
webs are deformed, making any deformation of the webs easy to
foresee. By means of the first and third webs that are essentially
aligned with each other to create an essentially straight web
course, the stability of the lattice structure is enhanced.
[0026] In a further preferred embodiment, the web connector can
have a wasp-waisted shape. The wasp-waisted shape appears, in
particular, as a tapering of the cross section of the web
connector, wherein the cross section is preferably formed in a
circumferential direction of the lattice structure. The
wasp-waisted embodiment of the web connector further enhances the
flexibility of the lattice structure, particularly without any
negative effect on the radial force.
[0027] To achieve high bending flexibility and longitudinal-axial
stability of the lattice structure in a guiding state, it is
preferred if the connector axis, at an expansion degree of the
lattice structure of 5% to 15%, in particular 8% to 12%, in
particular 10% or 9.9%, at an angle of not more than 5 degrees, in
particular not more than 4 degrees, in particular not more than 3
degrees, in particular not more than 2 degrees, in particular not
more than 1 degrees, is aligned to the longitudinal axis of the
lattice structure. At an expansion degree of the lattice structure
of 5% to 15%, in particular 8% to 12%, in particular 10% or 9.9%,
the connector axis can also be aligned parallel to the longitudinal
axis of the lattice structure.
[0028] Alternatively or additionally, at an expansion degree of at
least 90%, in particular at least 95%, in particular at least 98%,
in particular 100%, at an angle of not more than 5 degrees, in
particular not more than 4 degrees, in particular not more than 3
degrees, in particular not more than 2 degrees, in particular not
more than 1 degrees, the connector can be aligned to the
longitudinal axis of the lattice structure. At an expansion degree
of the lattice structure of at least 90%, in particular at least
95%, in particular at least 98%, in particular 100%, the connector
axis can also be aligned parallel to the longitudinal axis of the
lattice structure. The 100% expansion degree corresponds to the
fully expanded production state of the lattice structure.
[0029] The following applies to the intermediate states of the
lattice structure:
[0030] At an expansion degree of 40% to 50%, in particular 42% to
48%, in particular 44.4%, the connector axis with the longitudinal
axis of the lattice structure can enclose an angle of 15 degrees to
20 degrees, in particular 16 degrees to 19 degrees, in particular
18 degrees.
[0031] Moreover, at an expansion degree of 60% to 70%, in
particular 62% to 68%, in particular 66.7%, the connector axis with
the longitudinal axis of the lattice structure can enclose an angle
of 12 degrees to 18 degrees, in particular 13 degrees to 17.5
degree, in particular 14 degrees to 17 degrees, in particular 16
degrees.
[0032] At an expansion degree of 80% to 90%, in particular 82% to
90%, in particular 84% to 89.5%, in particular 86% to 89%, in
particular 88.9%, it is also conceivable for the connector axis
with the longitudinal axis of the lattice structure to enclose an
angle of 5 degrees to 12 degrees, in particular 6 degrees to 11
degrees, in particular 7 degrees to 10 degrees, in particular 8
degrees.
[0033] The aforementioned expansion degrees and ranges of expansion
degrees can be randomly combined with their correlated angles and
angle ranges. Particularly preferred embodiments provide, for
example, for the connector axis, at an expansion degree of the
lattice structure of 9.9% and/or 100%, to be aligned parallel to
the longitudinal axis of the lattice structure. At an expansion
degree of 44.4%, the connector axis with the longitudinal axis of
the lattice structure can enclose an angle of 18 degrees, at an
expansion degree of 66.1% an angle of 16 degrees can be enclosed,
and at an expansion degree of 88.9%, an angle of 8 degrees can be
enclosed.
[0034] The lattice structure can generally be provided as
self-expandable. Specifically, the lattice structure can include a
super-elastic material, particularly a nickel-titanium alloy,
preferably nitinol. The lattice structure can also be made of one
piece. In particular, the lattice structure can consist of a
super-elastic material, in particular a nickel-titanium alloy, such
as nitinol. Super-elastic materials of the aforementioned type have
a high elasticity that facilitates the rotation of the web
connectors, in particular without plastic deformation. Moreover,
super-elastic materials of this type provide sufficient radial
force to allow for radial expansion of the lattice structure, even
against the resistance of a vascular wall. Nickel-titanium alloys
also have shape memory properties that contribute advantageously to
self-expandability.
[0035] With respect to the dimensions of the lattice structure, it
is of advantage when the lattice structure in the production state
has a cross sectional diameter of between 3.5 mm and 6 mm, in
particular 3.5 mm or 4.5 mm, or 6 mm. The aforementioned values
apply to the production state in which the lattice structure is
fully expanded. In the implanted state the lattice structure
preferably has a cross-sectional diameter that is smaller by 0.5 mm
to 1.5 mm than in the production state. This ensures that the
lattice structure generates sufficient radial force to be firmly
anchored in a vessel of the body.
[0036] In addition, in the circumferential direction the lattice
structure can have between three and six, in particular between
three and nine, preferably six, immediately adjoining cells that
form a cell ring. In other words, in preferred embodiments the
lattice structure has a ring of cells, wherein the number of cells
is limited to the aforementioned values or the ranges of values.
Additional embodiments can provide for the lattice structure in the
circumferential direction to have more than twelve, in particular
between twelve and 48, immediately adjacent cells that form a cell
ring.
[0037] In general, the lattice structure can have cells, each of
which is delimited by four webs. A first and a third web can have a
first web width, and a second and fourth web can have a second web
width. The ratio between the first web width and the second web
width lies preferably between 1:1.1 and 1:3, in particular between
1:1.1 and 1:1.5, in particular between 1:1.25 and 1:1.5, in
particular between 1:1.1 and 1:1.3, and is preferably 1:1.3, 1:1.25
or 1:1.2. The web width ratio affects the rotatability of the web
connector and ensures sufficient radial expandability of the
lattice structure in highly wound vascular anatomies.
[0038] To achieve an optimum web width ratio, the number of cells
in a cell ring of the lattice structure must also be considered. In
a lattice structure that has a cell ring with three to nine cells,
in particular six cells, it is therefore preferred when the ratio
between the first web width and the second web width is preferably
between 1:1.1 and 1:1.5, in particular between 1:1.1 and 1:1.3, and
preferably 1:1.3. In a lattice structure having a cell ring with
more than twelve cells, in particular between twelve and 48, the
ratio between the first web width and the second web width lies
preferably between 1:1.1 and 1:3, in particular 1:1.25 or
1:1.2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In the following, the invention is explained in greater
detail by means of an exemplary embodiment and with reference to
the enclosed schematic drawings. The drawings show:
[0040] FIG. 1: a lateral view of a medical device according to this
invention in a guiding state, in particular at an expansion degree
of 9.9%;
[0041] FIG. 2. a detail view of a web connector of the medical
device according to FIG. 1;
[0042] FIG. 3: a lateral view of the medical device according to
FIG. 1 in a partially expanded state, in particular at an expansion
degree of 44.4%;
[0043] FIG. 4: a detail view of a web connector of the medical
device according to FIG. 3;
[0044] FIG. 5: a lateral view of the medical device according to
FIG. 1 in a partially expanded state, in particular at an expansion
degree of 66.7%;
[0045] FIG. 6: a detail view of a web connector of the medical
device according to FIG. 5;
[0046] FIG. 7: a lateral view of the medical device according to
FIG. 1 in a partially expanded state, in particular at an expansion
degree of 88.9%;
[0047] FIG. 8: a detail view of a web connector of the medical
device according to FIG. 7;
[0048] FIG. 9: a lateral view of the medical device according to
FIG. 1 in the production state, in particular at an expansion
degree of 100%;
[0049] FIG. 10: a detail view of a web connector of the medical
device according to FIG. 9;
[0050] FIG. 11: a diagram showing the angles between the web
connector and the longitudinal
[0051] axis of the lattice structure in relation to the expansion
degree in the medical device according to FIG. 1;
[0052] FIG. 12: a detail view of a web connector of the medical
device according to FIG. 1 at an expansion degree of 44.4% showing
the neutral fibers of the webs;
[0053] FIG. 13: a detail view of the web connector according to
FIG. 12, showing the longitudinal displacement of the cell tips of
neighboring cells; and
[0054] FIG. 14: a detail view of the web connector according to
FIG. 12, showing the staggering of the neutral fibers of
diametrically opposite webs.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The accompanying FIGS. show a medical device suited for
insertion into a hollow body organ. To this effect, the medical
device has, in particular, a lattice structure 10 that is
compressible and expandable. In other words, the lattice structure
10 can assume a guiding state in which the lattice structure 10 has
a relatively small cross-sectional diameter. The lattice structure
10 is preferably self-expandable, so that the lattice structure 10
automatically expands to a maximum cross-sectional diameter without
the influence of external forces. The state in which the lattice
structure 10 has a maximum cross-sectional diameter corresponds to
the production state. In the production state the lattice structure
10 has an expansion degree of 100%. An expansion degree of 100%
thus corresponds to the maximum cross-sectional diameter which the
lattice structure 10 can automatically assume. In this state the
lattice structure 10 exerts no radial force of any kind.
[0056] The lattice structure 10 is preferably formed of one piece.
In particular, the lattice structure 10 can be cylindrical, at
least in some sections. The lattice structure 10 is preferably made
of a tubular blank by a laser-cutting method. The laser cutting
process exposes the individual webs 11, 12, 13, 14 of the lattice
structure. The areas removed from the blank form cells 30 of the
lattice structure 10.
[0057] The cells 30 have essentially the basic form of a rhomboid.
In FIG. 9, this can be clearly seen. In particular, the cells 30
are delimited by four webs 11, 12, 13, 14 each, wherein the webs
11, 12, 13, 14 can at least in part have a curved course, in
particular an S-shaped course. Each cell 30 has cell tips 31, 32
which determine the corner points of the rhomboid basic shape. Each
cell tip 31, 32 is arranged on web connectors 20, each of which
integrally connects four webs 11, 12, 13, 14 with each other. Four
webs 11, 12, 13, 14 each extend from each web connector 20, and
each web 11, 12, 13, 14 is assigned to two cells 30. Each web 11,
12, 13, 14 delimits the cells 30.
[0058] As a rule, the lattice structure 10 can assume several
different states that are distinguished by the expansion degree of
the lattice structure 10. An expansion degree of 0% corresponds to
a theoretical cross-sectional diameter of 0 mm of the lattice
structure 10. In practice, such an expansion degree is not
achievable. The smallest expansion degree possible in practice is
preferably not higher than 10%. In this maximally compressed state
the lattice structure 10 is guided to the treatment site through a
catheter. Within the framework of the application, this state is
called the guiding state. In the embodiments shown in the FIGS.,
the lattice structure 10 has an expansion degree of 9.9% in the
guiding state.
[0059] FIG. 1 shows the lattice structure 10 in the guiding state.
It can be clearly seen that the webs 11, 12, 13, 14 partially rest
against each other in a circumferential direction, thus blocking
any further compression. In other words, the web width of the
individual webs 11, 12, 13, 14 restricts the compressibility of the
lattice structure 10. It can also be seen that each of the web
connectors 20 is essentially arranged on a common circumferential
line. Overall, several cells 30 thus form a cell ring 34 in a
circumferential direction of the lattice structure 10. The entire
lattice structure 10 is formed by several cell rings 34 that are
connected with each other longitudinally.
[0060] It is pointed out in this connection that the lattice
structure 10 can only be formed in some sections from
interconnected cell rings that have the same cross-sectional
diameter. It is in fact also possible for the lattice structure 10
to have, in some sections, a geometry other than a cylindrical one.
The lattice structure can, at least at one proximal end, be
funnel-shaped, for example. A configuration of this type is of
advantage in medical devices that are used as thrombus catchers or
generally as thrombectomy devices. In such cases, the lattice
structure 10 can essentially form a basket-like structure. Lattice
structures 10 that are entirely cylindrical are used in medical
devices that form stents. Stents can be used to support blood
vessels, or generally in hollow body organs and/or to cover
aneurysms.
[0061] In FIG. 2, a web connector 20 of the lattice structure 10
according to FIG. 1 is shown in detail. The web connector 20
interconnects four webs 11, 12, 13, 14. For simplicity's sake,
within the framework of the application, the webs 11, 12, 13, 14
that are merged at a web connector 20 are numbered
counter-clockwise to allow for a clear allocation. This allows a
first web 11 and a second web 12 to be assigned to a first cell 30,
and a third web 13 and a fourth web 14 to be assigned to a second
cell 30, wherein the cells 30 are immediately adjacent to each
other in a longitudinal direction of the lattice structure 10. In
other words, the web connector 20 separates two cells 30 of the
lattice structure 10 that are longitudinally arranged adjacent to
each other. In the area of the web connector 20, each cell 30 forms
cell tips 31, 32. A first cell tip 31 is bounded by the first web
11 and the second web 12. A second cell tip 32 is delimited by the
third web 13 and the fourth web 14.
[0062] Each cell tip 31, 32 forms or encompasses a curvature 33.
The curvature 33 results from the transition of the lateral
surfaces of the adjoining webs 11, 12, 13, 14 that are
circumferentially aligned. Specifically, the first cell tip 31
forms a curvature 33 that results from the transition of the first
web 11 to the second web 12 in the area of the web connector 20.
Accordingly, the curvature 33 of the second cell tip 32 is created
by a curved transition between the third web 13 and the fourth web
14 at the web connector 20. The curvatures 33 preferably take a
parabolic shape. Each curvature 33 has a maximum or a vertex, i.e.,
a point where the curvature radius is smallest. The distance
between the vertices of the curvatures 33 on opposite sides of a
web connector 20 corresponds to the shortest distance between the
cell tips 31, 32. The connecting line, i.e., the distance between
the two maxima or the vertices of the curvatures 33 forms the
connector axis 21. In other words, the connector axis 21
corresponds to the shortest distance between the two curvatures 33
of the first cell tip 31 and the second cell tip 32.
[0063] The connector axis 21 identifies the alignment of the web
connector 20 with respect to different degrees of expansion.
Generally, the angle between the connector axis 21 and the
longitudinal axis 15 of the lattice structure 10 changes when the
lattice structure 10 is compressed or expanded. In the guiding
state, the connector axis 21 is preferably aligned parallel to the
longitudinal axis 15 of the lattice structure 10. It is, however,
also possible for the connector axis 21 in the guiding state to be
arranged at an angle to the longitudinal axis 15 of the lattice
structure 10. The angle is preferably not more than 5 degrees, in
particular not more than 4 degrees, in particular not more than 3
degrees, in particular not more than 2o, in particular not more
than 1 degree.
[0064] In the FIGS., the longitudinal axis 15 of the lattice
structure 10 is shown by a dot-dash line with the description
"global stent axis." FIG. 2 shows that the cell tips 31, 32 in the
guiding state are essentially arranged longitudinally on opposite
sides, particularly without any staggering in a circumferential
direction. In this configuration, the lattice structure 10 has an
especially high axial stability. This is of advantage when the
lattice structure 10 is threaded through a catheter. In particular,
the cell tips 31, 32 support each other longitudinally-axially,
i.e., parallel to the longitudinal axis 15.
[0065] When the lattice structure 10 is released from a catheter or
any guiding system in general, the lattice structure 10
automatically expands radially. In so doing, the lattice structure
10 passes through several degrees of expansion until the lattice
structure 10 attains the implanted state. In the implanted state
the lattice structure 10 preferably applies radial force to the
surrounding vascular walls. The implanted state preferably
corresponds to an expansion degree of the lattice structure 10 that
is smaller than 100% and greater than 10%. The implanted state is
also known as "intended use configuration."
[0066] In the FIGS. 3-8, the lattice structure 10 or the web
connector 20 is shown at different expansion degrees. FIG. 3 thus
shows, by way of example, a lateral view of the lattice structure
10 at a degree of expansion of 44.4%. In spite of the radial
expansion of the lattice structure 10, it is easy to see that the
web connectors 20 are further arranged on a common circumferential
line. In particular, upon the expansion of the lattice structure 10
no longitudinal-axial staggering of the various web connectors 20
takes place. The cells 30 noticeably expand, causing the adjacent
webs 11, 12, 13, 14 to unfold chevron-like in a circumferential
direction. Thus, as the lattice structure 10 expands, the cell
height, measured in the circumferential direction of the lattice
structure 10, increases. Simultaneously, due to the foreshortening
effect the cell width is reduced, determining the width of the cell
30 in the longitudinal direction of the lattice structure 10.
[0067] FIG. 4 shows the web connector 20 of the lattice structure
10 at an expansion degree of the lattice structure 10 of 44.4%.
Thus, FIG. 4 is a detail view of FIG. 3. It is easily seen that the
cell tips 31, 32 are staggered to each other by the expansion of
the lattice structure 10 circumferentially. In particular, the web
connector 20 turns or rotates during the expansion of the lattice
structure 10, causing an angular displacement between the connector
axis 21 and the longitudinal axis 15 of the lattice structure 10.
At an expansion degree of 44.4%, the angular displacement is
preferably approximately 18 degrees. Specifically, at an expansion
degree of 44.4% an angle is created between the connector axis 21
and the longitudinal axis 15 of the lattice structure 10, said
angle assuming a value of 18 degrees. The rotation of the web
connector 20 occurs during the transition of the lattice structure
10 from the guiding state up to an expansion degree of 44.4%, or
generally of less than 50% essentially in a counter-clockwise
direction.
[0068] In FIG. 4 it can also be seen that the connector axis 21
transects the longitudinal axis 15 of the lattice structure 10. The
intersection between the connector axis 21 and the longitudinal
axis 15 of the lattice structure 10 is called the rotation point
16. The rotation point 16 describes the point at the web connector
20 around which the web connector 20 rotates. The web connector 20
thus rotates around the rotation point 16 as the lattice structure
10 expands, during which the rotational direction can change.
[0069] FIG. 5 shows a further intermediate state of the lattice
structure 10, in particular at an expansion degree of 66.7%. In
this state as well, the web connectors 20 continue to be on a
common circumferential line. The cells 30, compared to the
intermediate state according to FIG. 4, are identifiable by their
greater height and a smaller width.
[0070] In the detail view according to FIG. 6, the web connector 20
is shown at an expansion degree of the lattice structure 10 of
66.7%. The web connector 20 has a connector axis 21 that is
arranged at an angle of 16 degrees to the longitudinal axis 15 of
the lattice structure 10. [The invention]generally provides that,
at an expansion degree of greater than 50%, the angle between the
connector axis 21 and the longitudinal axis 15 of the lattice
structure 10 is smaller than at an expansion degree of the lattice
structure 10 of less than 50%. In other words, the rotational
direction of the web connector 20 changes when the lattice
structure 10 expands. The change of the rotational direction occurs
preferably at an expansion degree of approximately 50%, in
particular at an expansion degree of between 44% and 45%. During
the expansion of the lattice structure 10, the web connector 20
first turns counter-clockwise, and then changes its rotational
direction to turn in a clockwise direction.
[0071] At an expansion degree of 88.9%, i.e., in an intermediate
state as shown in FIGS. 7 and 8, the web connector 20 is at an
angle to the longitudinal axis 15 of the lattice structure 10 that
is smaller than at an expansion degree of 44.4% and 66.7%. As shown
in FIG. 8, the angle displacement between the connector axis 21 and
the longitudinal axis 15 of the lattice structure 10 at an
expansion degree of 88.9% measures approximately 8 o. In other
words, the staggering between the cell tips 31 and 32 changes in a
circumferential direction. FIG. 7 shows clearly that during an
intermediate state which essentially corresponds to an expansion
degree of approximately 90%, the cell height almost approximates
the cell width of cell 30. The web connectors 20 of the lattice
structure 10 are further arranged on a common circumferential line.
The same applies to the web connectors 20 in a longitudinal
direction of the lattice structure 10.
[0072] In general, when the lattice structure 10 expands, the web
connectors 20 of the lattice structure 10 do not change their
alignment relative to each other, both circumferentially and
longitudinally. Instead, the alignment of the connector axis 21 of
each individual web connector 20 is changed. In other words, while
the web connectors 20 turn when the lattice structure 10 expands,
they essentially maintain their relative position with respect to
adjoining web connectors 20 in a longitudinal and circumferential
direction. Only the distance between the web connectors 20 is
changed, at which the web connectors 20 move away from each other
in straight lines of movement or, when the lattice structure 10 is
compressed, approach each other.
[0073] FIG. 9 shows a lateral view of the lattice structure 10
showing the lattice structure 10 in the production state. In other
words, the lattice structure 10 is fully expanded. The lattice
structure 10 essentially is in a state free of radial force. In
this state the cell 30 has a cell height that essentially
corresponds to the cell width. The basic shape of the cell in this
case is essentially a square and thus corresponds to an equiangular
or a rectangular rhomboid. The webs 11, 12, 13, 14 of cell 30,
however, do not extend in a straight line. However, if the cell
tips 31 and 32 of the cell are connected to each other in a
straight line, a square basic form will essentially be seen.
[0074] In FIG. 10 the web connector 20 is shown in detail when the
lattice structure 10 is present in the production state according
to FIG. 9. As a result of the alternating rotation of the web
connector 20 as the lattice structure 10 expands, the web connector
20 in the production state again assumes its original alignment. In
particular, the connector axis 21 in the production state is
aligned parallel to the longitudinal axis 15 of the lattice
structure 10. The cell tips 31, 32 are thus arranged longitudinally
along the lattice structure 10 on the web connector 20 on opposite
sides. In other words, the cell tips 31, 32 are aligned with each
other. It is, however, also possible for the connector axis 21 in
the production state to be arranged at an angle to the longitudinal
axis 15 of the lattice structure 10. The angle is preferably not
more than 5 degree, in particular not more than 4 degrees, in
particular not more than 3 degree, in particular not more than 2
degrees, in particular not more than 1 degree.
[0075] FIG. 11 is a diagram of the course of the web connector
rotation as the lattice structure 10 expands. Beginning at a
guiding state that corresponds to an expansion degree of
approximately 10%, the angle between the connector axis 21 and the
longitudinal axis 15 of the lattice structure 10 initially
increases. In particular, the rotational angle increases to a value
of up to approximately 18 degree. This value is reached at an
expansion degree of approximately 44% to 45%. The rotational
direction of the web connector 20 then changes, decreasing the
angle between the connector axis 21 and the longitudinal axis 15 of
the lattice structure 10. In particular, the angle between the
connector axis 21 and the longitudinal axis 15 of the lattice
structure 10 diminishes until the fully expanded state or the
production state of the lattice structure 10 is reached. In the
production state, i.e., at an expansion degree of 100%, the angle
between the connector axis 21 and the longitudinal axis 15 of the
lattice structure 10 is 0%. Thus, the connector axis 21 is arranged
parallel to the longitudinal axis 15 of the lattice structure 10.
In general, the connector axis 21 of the web connector 20 is
aligned parallel to the longitudinal axis 15 of the lattice
structure 10 when the lattice structure 10 is in the guiding state
as well as in the production state. In the intermediate states
between the guiding state and the production state, an angle
appears between the connector axis 21 and the longitudinal axis 15
of the lattice structure 10.
[0076] FIG. 12 shows an exemplary web connector 20 of the lattice
structure 10 where the lattice structure 10 is at a degree of
expansion of 44.4%. FIG. 12 additionally shows the neutral fibers
17 of the individual webs 11, 12, 13, 14, drawn in a dot-dash line.
A further dot-dash line that runs horizontally within the image
plane represents the position of the longitudinal axis 15 of the
lattice structure 10.
[0077] A total of four webs 11, 12, 13, 14 converge at the web
connector 20. The webs 11, 12, 13, 14 are distinguished, on the one
hand, by their shape and, on the other hand, by their web width. In
particular, a first web 11 and a third web 13 have a web width that
is smaller than the web width of the second web 12 and the fourth
web 14. This considers the average web width. It can also be seen
that the first web 11 and the third web 13, essentially aligned
with each other in a straight line, debouch into the web connector
20. Specifically, the first web 11 and the third web 13 each have a
neutral fiber 17, wherein the neutral fibers 17 of the first web 11
and the third web 13 are aligned with each other. Thus, the neutral
fibers 17 of the first web [11] and the third web 13 essentially
merge into each other in a straight line, so that a common neutral
fiber 17 is created that traverses the web connector 20.
[0078] The second web 12 and the fourth web 14 differ in shape from
the first web 11 and the third web 13. Characteristic for the
second web 12 and the fourth web 14 is their curved course in the
area of the web connector 20. Specifically, the second web 12 and
the fourth web 14 each have an angular end section 19. The angular
end sections 19 each form a root 18 of the second web 12 and the
fourth web 14. Specifically, the second web 12 and the fourth web
14 each have a broadened root 18.
[0079] The diametrically opposing webs 12, 14, described as the
second web 12 and the fourth web 14, essentially debouch staggered
to each other into the web connector 20. The course of the neutral
fibers 17 of webs 11, 12, 13, 14 shows this clearly. Both the
second web 12 and the fourth web 14 each have a neutral fiber 17
that meets the neutral fiber, in particular the common neutral
fiber 17, of the first web 11 and the third web 13 at an angle. The
angle between the neutral fiber 17 of the second web 12 and the
common neutral fiber 17 of the first web [11] and the third web 13
preferably measures 90 degrees. The same applies to the neutral
fiber 17 of the fourth web 14 which also meets the common neutral
fiber 17 of the first web 11 and the third web 13 at a preferred
angle of 90 degrees. The neutral fibers 17 of the second web 12 and
the fourth web 14, by contrast, are aligned to each other in
staggered fashion. FIG. 14 shows the web connector 20 of FIG. 12
illustrating the fiber displacement V between the neutral fibers 17
of the second web 12 and the fourth web 14.
[0080] On principle, an angle of 90 degrees between the neutral
fibers of the second web and the fourth web with respect to the
common neutral fiber 17 of the first web 11 and the third web 13,
i.e., a vertical alignment is preferred. However, different angles
are also possible. The neutral fibers of the second web 12 and the
fourth web 14, for example, can also meet the common neutral fiber
17 of the first web 11 and the third web 13 at an angle of less
than 90 degrees, in particular not more than 75 degrees, in
particular not more than 55 degrees, in particular not more than 50
degrees, in particular not more than 45 degrees.
[0081] In general, FIG. 12 shows that the first web 11 and the
third web 13 are essentially arranged in line with each other or
true to the line. By contrast, the second web 12 and the fourth web
14 take an S-shaped course in the area of the web connector 20. The
angular end sections 19 of the second web 12 and the fourth web 14
form an intermediate section, formed by the web connector 20,
between two opposing bends of the S-shaped course of the two
diametrically opposite webs 12, 14, that are described as the
second web 12 and the fourth web 14.
[0082] FIG. 13 shows, by way of clarification, the web connector
according to FIG. 12, which clearly shows the displacement between
the cell tips 31, 32 in a circumferential direction. The web
connector 20 according to FIG. 13 has a connector axis 21 that is
arranged in an angular displacement to the longitudinal axis 15 of
the lattice structure 10. The angular displacement is preferably
approximately 18 degrees. In other words, FIG. 13 shows the web
connector 20 at an expansion degree of the lattice structure 10 of
approximately 44.4%. In this intermediate state of the lattice
structure 10, there exists a circumferential displacement V between
the end points 22 of the connector axis 21, said displacement being
shown by appropriate arrows in FIG. 13. The circumferential
displacement V in relation to the web width of the second web 12
and the fourth web 14 is preferably at least 0.5, in particular at
least 1.0, in particular at least 1.5, in particular at least 2.0.
In the embodiment according to FIG. 13, the circumferential
displacement V in relation to the web width of the second web 12
and the fourth web 14 is 1.0. In other words, the circumferential
displacement of the cell tips 31, 32 or of the end points 22 of the
connector axis 21 corresponds to the web width of the second web 12
or the fourth web 14. The circumferential displacement V is a
function of the angular displacement. In this respect, the
circumferential displacement V in the guiding state and/or the
production state of the lattice structure 10 is preferably
zero.
[0083] On principle, the invention provides that the rotation of
the web connector 20 can be not more than 30 degrees, in particular
not more than 20 o, in particular not more than 18 degrees, in
particular not more than 15 degrees, in particular not more than 10
degrees, in particular not more than 5 degrees. In the embodiments
illustrated the angular displacement between the connector axis 21
and the longitudinal axis 15 of the lattice structure 10 is a
maximum of 18 degrees, in particular at an expansion degree of the
lattice structure 10 of 44.4%.
[0084] For increased flexibility, it is of advantage for the webs
11, 12, 13, 14 to have different web width. Diametrically opposite
webs, particularly the first web 11 and the third web 13, can have
a first web width and crosswise arranged, diametrically opposite
webs; particularly the second web 12 and the fourth web 14 can have
a second web width. The ratio between the first web width and the
second web width, i.e., the web width ratio, can be at least
1:1.25, in particular at least 1:1.5, in particular at least
1:1.75, in particular at least 1:2.
[0085] A web width ratio of 1:1.2 or 1:1.3 was found to be
particularly suitable, in particular for a lattice structure 10
that has six cells 30 in the circumferential direction. For a
lattice structure 10 having more than twelve cells 30 that are
arranged immediately adjacent to each other circumferentially, the
web width ratio is preferably 1:1.2 or 1:1.25, respectively.
[0086] In principle, the flexibility of the lattice structure 10 is
increased when a relatively small web width ratio is chosen. At a
web width ratio of 1:1.25 (the web width of the first web 11 or the
third web 13, respectively, to the web width of the second web 12
or the fourth web 14, respectively), an especially high flexibility
has been observed, since this leads to an improved rotation of the
web connector 20. At the same time, a web width ratio of this type
provides a sufficient expansion force.
[0087] In general, [the invention] also provides for the lattice
structure 10 to have a maximum of 48, in particular a maximum of
24, in particular a maximum of 16, in particular a maximum of 12,
in particular a maximum of 6 cells 30 in a circumferential
direction. In other words, each cell ring 34 of the lattice
structure 10 can be formed of a maximum of 48, in particular a
maximum of 24, in particular a maximum of 16, in particular a
maximum of 12, in particular a maximum of 6 cells.
[0088] In a specific embodiment, the medical device forms a stent
having a lattice structure 10. The lattice structure 10 or the
stent can have an outer diameter in the production state of 3.5 mm
or 4.5 mm respectively. The axial length of the stent or the
lattice structure 10, is preferably 15 mm, 20 mm or 35 mm. The web
width ratio is preferably 1:1.25, wherein the first web width is 40
.mu.m and the second web width is 32 .mu.m. The lattice structure
10 preferably takes the form of a six-cell lattice structure 10,
i.e., the lattice structure 10 has cell rings 34 with six cells 30
each.
[0089] In principle, the invention is suited not only for use as a
stent, but also as a clot retriever or flow diverter, particularly
when the lattice structure 10 is laser-cut.
LIST OF REFERENCE SYMBOLS
[0090] 10 Lattice structure [0091] 11 first web [0092] 12 second
web [0093] 13 third web [0094] 14 fourth web [0095] 15 Longitudinal
axis [0096] 16 Rotation point [0097] 17 Neutral fiber [0098] 18
Root [0099] 19 Angular end section [0100] 20 Web connector [0101]
21 Connector axis [0102] 22 End point [0103] 30 Cell [0104] 31
First cell tip [0105] 32 Second cell tip [0106] 33 Curvature [0107]
34 Cell ring
* * * * *